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प्रश्न
Using Huygens's construction of secondary wavelets explain how a diffraction pattern is obtained on a screen due to a narrow slit on which a monochromatic beam of light is incident normally.
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उत्तर
Consider a parallel beam of light from a lens falling on a slit AB. As diffraction occurs, the pattern is focused on the screen with the help of lens L2. We will obtain a diffraction pattern that is a central maximum at the centre O, flanked by a number of dark and bright fringes called secondary maxima and minima.
Each point on the plane wave front AB sends out secondary wavelets in all directions. The waves from points equidistant from the centre C, lying on the upper and lower half, reach point O with zero path difference and, hence, reinforce each other producing maximum intensity at point O.
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संबंधित प्रश्न
Explain the construction of plane wavefront using Huygens’ principle.
What is the shape of the wavefront in the following case?
Light emerging out of a convex lens when a point source is placed at its focus.
Consider a plane wave front incident on a thin convex lens. Draw a proper diagram to show how the incident wave front traverses through the lens and after refraction focusses on the focal point of the lens, giving the shape of the emergent wave front.
Use Huygens' principle to verify the laws of refraction.
Using Huygens’ principle, verify the laws of reflection at a plane surface.
Using this principle draw a diagram to show how a plane wave front incident at the interface of the two media gets refracted when it propagates from a rarer to a denser medium. Hence verify Snell's law of refraction.
Huygens' principle of secondary wavelets may be used to
(a) find the velocity of light in vacuum
(b) explain the particle behaviour of light
(c) find the new position of a wavefront
(d) explain Snell's Law
Relation between ray and wavefront is ______.
Figure shows a standard two slit arrangement with slits S1, S2, P1, P2 are the two minima points on either side of P (Figure). At P2 on the screen, there is a hole and behind P2 is a second 2-slit arrangement with slits S3, S4 and a second screen behind them.
Represent diagrammatically how the incident planar wavefronts of wavelength λ pass through an aperture of size d, when d is approximately equal to λ.
